Note: This is a seattlepi.com reader blog. It is not written or edited by the P-I. The authors are solely responsible for content. E-mail us at newmedia@seattlepi.com if you consider a post inappropriate..

The Ice was Nice 3

I slept on the multi-year pack ice in the high Arctic Ocean in the ‘70s when we had a large camp there for a year, called the Arctic Ice Dynamics Joint Experiment. The average ice thickness was about 10-feet then. The total extent of pack ice in the winter included the whole Arctic basin.

A new study has found that the oldest and thickest Arctic sea ice is disappearing at a faster rate than the younger and thinner ice at the edges of the ice cap. The rapid disappearance of older ice makes the Arctic Ocean’s sea ice cap more vulnerable to further decline.

The average ice thickness now is about 3-feet. The Arctic multi-year ice “extent” (all areas where at least 15 percent of the ocean surface is covered by multi-year ice) has been vanishing at a rate of –15.1 percent per decade, while the “area” covered by multi-year ice has been shrinking by –17.2 percent per decade.

This new data must be inserted in the climate models, together with the methane release that will accompany the ice decrease. The models are imperfect, but it’s bothersome that errors seem to be always made on the conservative side – positive feedbacks to GW are neglected.

The findings were published in February 2012 in the Journal of Climate.

Note: This is a seattlepi.com reader blog. It is not written or edited by the P-I. The authors are solely responsible for content. E-mail us at newmedia@seattlepi.com if you consider a post inappropriate..